1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
/** @file keymaker.cc
* @brief Build key strings for MSet ordering or collapsing.
*/
/* Copyright (C) 2007,2009,2011,2015 Olly Betts
* Copyright (C) 2010 Richard Boulton
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <config.h>
#include "xapian/keymaker.h"
#include "xapian/document.h"
#include <string>
#include <vector>
using namespace std;
namespace Xapian {
KeyMaker::~KeyMaker() { }
string
MultiValueKeyMaker::operator()(const Xapian::Document & doc) const
{
string result;
auto i = slots.begin();
// Don't crash if slots is empty.
if (rare(i == slots.end())) return result;
size_t last_not_empty_forwards = 0;
while (true) {
// All values (except for the last if it's sorted forwards) need to
// be adjusted.
//
// FIXME: allow Xapian::BAD_VALUENO to mean "relevance?"
string v = doc.get_value(i->slot);
bool reverse_sort = i->reverse;
if (v.empty()) {
v = i->defvalue;
}
if (reverse_sort || !v.empty())
last_not_empty_forwards = result.size();
if (++i == slots.end() && !reverse_sort) {
if (v.empty()) {
// Trim off all the trailing empty forwards values.
result.resize(last_not_empty_forwards);
} else {
// No need to adjust the last value if it's sorted forwards.
result += v;
}
break;
}
if (reverse_sort) {
// For a reverse ordered value, we subtract each byte from '\xff',
// except for '\0' which we convert to "\xff\0". We insert
// "\xff\xff" after the encoded value.
for (string::const_iterator j = v.begin(); j != v.end(); ++j) {
unsigned char ch = static_cast<unsigned char>(*j);
result += char(255 - ch);
if (ch == 0) result += '\0';
}
result.append("\xff\xff", 2);
if (i == slots.end()) break;
last_not_empty_forwards = result.size();
} else {
// For a forward ordered value (unless it's the last value), we
// convert any '\0' to "\0\xff". We insert "\0\0" after the
// encoded value.
string::size_type j = 0, nul;
while ((nul = v.find('\0', j)) != string::npos) {
++nul;
result.append(v, j, nul - j);
result += '\xff';
j = nul;
}
result.append(v, j, string::npos);
if (!v.empty())
last_not_empty_forwards = result.size();
result.append("\0", 2);
}
}
return result;
}
}
|
